Variable Drag Area Tow System for Cable Tension Control
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Solution Overview
Problem
Towed systems face limitations in operational conditions due to increased droop at lower vessel speeds, restricting vessels from operating at varying altitudes or depths, and potentially causing damage to the towed system or its surroundings.
Innovation Solution
A variable drag area tow system with a device that adjusts its projected area based on velocity, using moveable drag fins and an expansion mechanism to maintain tension and reduce droop, allowing vessels to operate safely across a wider range of speeds and depths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the vessel speed decreases, then the drag induced by the system and tow cable decreases, but the droop increases causing operational limitations
Solution Approach 1:
The patent applies the dynamics principle by making the drag area of the towed system variable rather than fixed. The towed system includes adjustable drag surfaces that can be deployed or retracted to change the overall drag area. This allows the system to maintain optimal tension and droop control across varying vessel speeds, resolving the contradiction between speed reduction and operational capability.
Solution Approach 2:
The patent implements parameter changes by modifying the drag area parameter of the towed system. By adjusting the drag area based on vessel speed, the system maintains appropriate cable tension and droop characteristics. At lower speeds, increased drag area compensates for reduced dynamic tension, while at higher speeds, reduced drag area prevents excessive tension, thereby expanding operational conditions across the speed range.
2Ease of operation
If the drag area is increased to maintain tension at lower speeds, then droop is reduced, but the system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the towed system into modular components with independent drag control. The drag surfaces are segmented into adjustable sections that can be independently deployed or retracted. This modular approach allows for variable drag area control without requiring complete system redesign, thereby managing complexity while achieving droop control.
Solution Approach 2:
The patent implements universality by designing the towed system to perform multiple functions: it serves as both the primary towing target and the variable drag control mechanism. The same structural components that form the towed system also provide the adjustable drag surfaces, eliminating the need for separate drag control devices and reducing overall system complexity.
3Device complexity
If a fixed drag area system is used, then the system is simple to operate, but the operational speed range is limited
Solution Approach 1:
The patent transforms the static, fixed drag area system into a dynamic system with adjustable drag characteristics. The towed system incorporates movable drag surfaces that can be adjusted in real-time based on operational requirements and vessel speed. This dynamic capability expands the operational speed range while maintaining relatively simple system architecture through straightforward mechanical adjustment mechanisms.
Solution Approach 2:
The patent implements parameter changes by making the drag area a variable parameter rather than a fixed design constant. The system can adjust the drag area parameter to match different operational conditions and vessel speeds. This parameter variability is achieved through simple mechanical means such as deployable surfaces or adjustable angles, maintaining system simplicity while significantly enhancing adaptability across the speed range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The variable drag area system enhances operational conditions by maintaining tension and reducing droop, enabling safe towing at slower speeds and reducing the risk of damage, while minimizing the need for heavy tow cables and reducing operational restrictions.
Implementation Method 1
the drag induced by the system and the tow cable cause sufficient tension on the tow cable to minimize the droop
Data Source
AI summary
A variable drag area tow system including a tow cable, and a variable drag area device having a variable projected area, the variable drag area device is configured to have a smaller projected area as the velocity of the variable drag area device with respect to a fluid increases. A method of maintaining tension on a tow cable, the method including deploying at a first velocity a variable drag area device having a variable projected area, increasing the first velocity to a second velocity, and decreasing the projected area of the variable drag area device as the first velocity is increased to the second velocity.